18F RGD

PURPOSE: Due to the high expression of the integrin αvβ3 not only on endothelial cells, but also on mature osteoclasts and prostate cancer cells, imaging of osseous metastases with αvβ3-targeted tracers seems promising. However, little is known about the patterns of αvβ3-expression in metastasized prostate cancer lesions in-vivo. Thus we evaluated the uptake of the αvβ3-specific PET tracer [18F]Galacto-RGD for assessment of bone metastases in prostate cancer patients. RESULTS: [18F]Galacto-RGD PET identified 58/74 bone-lesions (detection rate of 78...

PURPOSE: Radiolabeled arginine-glycine-aspartic acid (RGD) peptides have been developed for PET imaging of integrin avβ3 in the tumor vasculature, leading to great potential for noninvasively evaluating tumor angiogenesis and monitoring antiangiogenic treatment. The aim of this study was to investigate a novel one-step labeled integrin-targeted tracer, 18F-AlF-NOTA-PRGD2, for PET/CT for detecting tumor angiogenesis and monitoring the early therapeutic efficacy of antiangiogenic agent Endostar in human nasopharyngeal carcinoma (NPC) xenograft model...

UNLABELLED: Integrins are upregulated on both tumor cells and associated vasculature, where they play an important role in angiogenesis and metastasis. Fluciclatide is an arginine-glycine-aspartic acid peptide with high affinity for αvβ3/αvβ5 integrin, which can be radiolabeled for PET imaging of angiogenesis. Thus, (18)F-fluciclatide is a potential biomarker of therapeutic response to antiangiogenic inhibitors. The aim of this study was to evaluate the reproducibility of (18)F-fluciclatide in multiple solid-tumor types...

Breast cancer is the leading cause of cancer deaths among women of all ages worldwide. With advances in molecular imaging procedures, it has been possible to detect breast cancer in its early stage, determine the extent of the disease to administer appropriate therapeutic protocol and also monitor the effects of treatment. By accurately characterizing the tumor properties and biological processes involved, molecular imaging can play a crucial role in minimizing the morbidity and mortality associated with breast cancer...

Angiogenesis is a requirement for tumor growth and metastasis. The angiogenic process depends on vascular endothelial cell migration and invasion, and is regulated by various cell adhesion receptors. Integrins are such a family of receptors that facilitate the cellular adhesion to and migration on extracellular matrix proteins in the intercellular spaces and basement membranes. Among 24 members of the integrin family, αvβ3 is studied most extensively for its role in tumor angiogenesis and metastasis. The αvβ3 is expressed at relatively low levels on epithelial cells and mature endothelial cells, but it is highly expressed on the activated endothelial cells of tumor neovasculature and some tumor cells...

Hexafluorobenzene (HFB) reacts with free thiols to produce a unique and selective perfluoroaromatic linkage between two sulfurs. We modified this chemical reaction to produce dimeric (18)F-RGD-tetrafluorobenzene (TFB)-RGD, an integrin αvβ3 receptor ligand. (18)F-HFB was prepared by a fluorine exchange reaction using K(18)F/K2.2.2 at room temperature. The automated radiofluorination was optimized to minimize the amount of HFB precursor and, thus, maximize the specific activity. (18)F-HFB was isolated by distillation and subsequently reacted with thiolated c(RGDfk) peptide under basic and reducing conditions...

OBJECTIVE: (18)F-Fluorodeoxyglucose ((18)F-FDG), (18)F-fluoro-3'-deoxy-3'-L-fluorothymidine ((18)F-FLT), (18)F-fluoromisonidazole ((18)F-FMISO), and (18)F-AlF-NOTA-PRGD2 ((18)F-RGD) are all commonly used PET tracers for tumor diagnosis based on different mechanisms of tissue uptake. This study compared the ex-vivo biodistribution and PET/computed tomography (CT) imaging studies of these four PET tracers in a xenograft prostate tumor-bearing mouse model. MATERIALS AND METHODS: Nude mice were inoculated with 5 × 10 PC-3 cells in the right armpit...

BACKGROUND: Inflammation and angiogenesis play an important role in atherosclerotic plaque rupture. Therefore, molecular imaging of these processes could be used for determination of rupture-prone atherosclerotic plaques. αvβ3 integrin is involved in the process of angiogenesis. Targeted imaging of αvβ3 integrin has been shown to be possible in previous studies on tumor models, using radiolabeled arginine-glycine-aspartate (RGD). Our aim was to investigate feasibility of ex vivo detection of αvβ3 integrin in carotid endarterectomy (CEA) specimens...

The fast kinetics and bioorthogonal nature of the tetrazine trans-cyclooctene (TCO) ligation makes it a unique tool for PET probe construction. In this study, we report the development of an (18)F-labeling system based on a CF3-substituted diphenyl-s-tetrazine derivative with the aim of maintaining high reactivity while increasing in vivo stability. c(RGDyK) was tagged by a CF3-substituted diphenyl-s-tetrazine derivative via EDC-mediated coupling. The resulting tetrazine-RGD conjugate was combined with a (19)F-labeled TCO derivative to give HPLC standards...

PURPOSE: We describe a noninvasive PET imaging method that monitors early therapeutic efficacy of BAY 87-2243, a novel small-molecule inhibitor of mitochondrial complex I as a function of hypoxia-inducible factor-1α (HIF1α) activity. EXPERIMENTAL DESIGN: Four PET tracers [(18)F-FDG, (18)F-Fpp(RGD)2, (18)F-FLT, and (18)F-FAZA] were assessed for uptake into tumor xenografts of drug-responsive (H460, PC3) or drug-resistant (786-0) carcinoma cells. Mice were treated with BAY 87-2243 or vehicle...

Peptides based on the cyclic Arg-Gly-Asp (RGD) sequence have been designed to antagonize the function of alpha(v)beta(3) integrin, thereby inhibiting angiogenesis. The conjugation of RGD peptides to radiolabeled gold nanoparticles (AuNP) produces biocompatible and stable multimeric systems with target-specific molecular recognition. The aim of this research was to evaluate the therapeutic response of 177Lu-AuNP-RGD in athymic mice bearing alpha(v)beta(3)-integrin-positive C6 gliomas and compare it with that of 177Lu-AuNP or 177Lu-RGD...

The α(v)β₃ integrin is highly expressed in prostate cancer (PCa), in which it is a key player in tumour invasion, angiogenesis and metastasis formation. Therefore, α(v)β₃ integrin is considered a very promising target for molecular imaging of PCa. This study tested the potential of the novel α(v)β₃ integrin affine agent [⁶⁸Ga]NOTA-RGD in comparison with the established [¹⁸F]fluoroethylcholine (FEC) and [¹⁸F]fluorodeoxyglucose (FDG) for assessing PCa using positron emission tomography (PET)...

A divalent knottin containing two separate integrin binding epitopes (RGD) in the adjacent loops, 3-4A, was recently developed and reported in our previous publication. In the current study, 3-4A was radiofluorinated with a 4-nitrophenyl 2-(18)F-fluoropropinate ((18)F-NFP) group and the resulting divalent positron emission tomography (PET) probe, (18)F-FP-3-4A, was evaluated as a novel imaging probe to detect integrin αvβ3 positive tumors in living animals. Knottin 3-4A was synthesized by solid phase peptide synthesis, folded, and site-specifically conjugated with (18/19)F-NFP to produce the fluorinated peptide (18/19)F-fluoropropinate-3-4A ((18/19)F-FP-3-4A)...

Musculoskeletal tumors comprise a multitude of tumor entities with different grades of malignancy, biological behavior, and therapeutic options. Positron emission tomography (PET) using the glucose analog [18F]fluorodeoxyglucose (FDG) is an established imaging modality for detection and staging of cancer, despite some shortcomings. Numerous studies have evaluated the role of PET imaging musculoskeletal tumors beyond FDG. The use of more specific novel PET radiopharmaceuticals such as the proliferation marker [18F]fluorodeoxythymidine (FLT), the bone-imaging agent [18F]sodium fluoride, amino acid tracers ([11C]methionine, [18F]fluoroethyltyrosine), or biomarkers of neoangiogenesis ([18F]galacto-RGD) can potentially provide insights into the biology of musculoskeletal tumors with focus on tumor grading, treatment monitoring, posttherapy assessment, and estimation of individual prognosis...

AIM: (18)F-DPA-714 is a PET tracer that recognizes macrophage translocator protein (TSPO), and (18)F-Alfatide II ((18)F-AlF-NOTA-E[PEG4-c(RGDfk)]2) is specific for integrin αvβ3. This study aims to apply these two tracers for longitudinal PET imaging of muscular inflammation, and evaluate the value of (18)F-DPA-714 in differentiating inflammation from tumor. METHODS: RAW264.7 mouse macrophage cells were used for cell uptake analysis of (18)F-DPA-714. A mouse hind limb muscular inflammation model was established by intramuscular injection of turpentine oil...

The development of RGD-based antagonist of αvβ3 integrin receptor has enhanced the interest in PET probes to image this receptor for the early detection of cancer, to monitor the disease progression and the response to therapy. In this work, a novel prosthetic group (N-(4-fluorophenyl)pent-4-ynamide or FPPA) for the (18)F-labeling of an αvβ3 selective RGD-peptide was successfully prepared. [(18)F]FPPA was obtained in three steps with a radiochemical yield of 44% (decay corrected). Conjugation to c(RGDfK(N3)) by the Cu(II) catalyzed Huisgen azido alkyne cycloaddition provided the [(18)F]FPPA-c(RGDfK) with a radiochemical yield of 29% (decay corrected), in an overall synthesis time of 140 min...

INTRODUCTION: Arylboronates afford rapid aqueous (18)F-labeling via the creation of a highly polar (18)F-aryltrifluoroborate anion ((18)F-ArBF3(-)). HYPOTHESIS: Radiosynthesis of an (18)F-ArBF3(-) can be successfully applied to a clinically relevant peptide. To test this hypothesis, we labeled dimeric-cylcoRGD, [c(RGDfK)]2E because a) it is molecularly complex and provides a challenging substrate to test the application of this technique, and b) [c(RGDfK)]2E has already been labeled via several (18)F-labeling methods which provide for a preliminary comparison...

PURPOSE: RGD peptide-based radiotracers are well established as integrin αvβ3 imaging probes to evaluate tumor angiogenesis or tissue remodeling after ischemia or infarction. In order to optimize the labeling process and pharmacokinetics of the imaging probes, we synthesized three dimeric RGD peptides with or without PEGylation and performed in vivo screening. PROCEDURES: Radiolabeling was achieved through the reaction of F-18 aluminum-fluoride complex with the cyclic chelator, 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA)...

INTRODUCTION: Positron Emission Tomography (PET) is a rapidly expanding, cutting edge technology for preclinical evaluation, cancer diagnosis and staging, and patient management. A one-step aqueous (18)F-labeling method, which can be applied to peptides to provide functional in vivo images, has been a long-standing challenge in PET imaging. Over the past few years, we have sought a rapid and mild radiolabeling method based on the aqueous radiosynthesis of in vivo stable aryltrifluoroborate (ArBF(3)(-)) conjugates...

BACKGROUND: Expression of αvβ3 integrin is increased after myocardial infarction as part of the repair process. Increased expression of αvβ3 has been shown by molecular imaging with 18F-galacto-RGD in a rat model. The 68Ga-labelled RGD compounds 68Ga-NODAGA-RGD and 68Ga-TRAP(RGD)3 have high specificity and affinity, and may therefore serve as alternatives of 18F-galacto-RGD for integrin imaging. METHODS: Left coronary artery ligation was performed in rats. After 1 week, rats were imaged with [13N]NH3, followed by 18F-galacto-RGD, 68Ga-NODAGA-RGD or 68Ga-TRAP(RGD)3 using a dedicated animal PET/CT device...